References
- Bates, H. F. & Albee, P. R., 1964. High latitude VLF propagation. University of Alaska, Report UAG-R154.
- Frisius, J., 1966. On the determination of VLF propagation parameters by field strength measure-ments over medium distances. Radio Sci. 1, 513.
- Kaufmann, P., Souza, R. M. & Mendes, A. M., 1968. A note on lower ionosphere equivalent height diurnal variation. Talus 20, in press.
- Wait, J. R., 1959. Diurnal change of ionospheric heights deduced from phase velocity measure-ments at VLF. Proc. IRE 47, 998.
- Wait, J. R. & Walters, L. C., 1963. Reflection of VLF radio waves from an inhomogeneous iono-sphere. Part I. Exponentially varying isotropic model. J. Reds. NBS 67D, 361.
- Watt, A. D. & Croghan, R. D., 1967. In VLF radio engineering (Edited by A. D. Watt), chapter 3. Pergamon Press, London, UK.